"Bane is someone ravaged by pain from a trauma suffered long ago," Nolan said. "And the mask dispenses a type of anesthetic that keeps his pain just below the threshold so he can function." ... Venom acts as a sort of super-steroid, further increasing Bane's already impressive physique into something more superhuman.

What was Bane's injury?

So during Talia's escape the prisoners attacked Bane and tore his face apart. The doctors' attempts to fix Bane's face left him in incredible agony, therefore he has to wear the mask: to keep his face "in place" and to ease his pain.

Was the Bane mask uncomfortable?

I'm genuinely a nice guy." So getting into bad guy mode isn't uncomfortable for Hardy. ... As if weren't bad enough that Hardy's voice has been completely muffled by Bane's signature look, the mask itself is apparently no picnic to wear in the first place. "Bane's mask is tight, actually," he said.